Coating apparatus



Dec. 15, LENZ COATING APPARATUS Filed Feb. 14'. 1946 u w HM.

. fllllll/llllf/ll Inventor: art Lehz, bg His A'tcorn'eg.

Patented Dec. 15, 1942 COATING APPARATUS Carl Lenz, Warren, Ohio, assignor to General Electric Company, a corporation of New York Application February 14, 1940, Serial No. 318,963 2 Claims. (01. 91-122) the type disclosed in United States Patent 2,l48,-

314 to D. K. Wright, in which said reflector section or member is part of the sealed enclosure surrounding the filamentary light source. The reflecting coating has been deposited on such concave members by resting the rim of the member on a gasket mounted ona suitable support, exhausting the air from the member, and then heating a quantity of the reflecting material to vaporize it and cause it to condense on the interior surface of the member. In the development of high production equipment for this purpose, heads for holding the concave members have bee designed which are suitable for an'indexing type machine, one such head construction being that disclosed in application Serial No. 318,962, of even date, Strickland et al. The head of this machine accommodates two members which are mounted on opposite sides of the head and face each other, and provides a single heater for vaporizing the reflecting coating. It is one of the objects of my invention to provide an improved head of this type for causing a uniform and satisfactory deposition of the reflecting material. Other features and advantages of the apparatus comprising my invention will appear from the following detailed description and the accompanying drawing of species thereof.

In the drawing, Fig. 1 is a sectional view of apparatus comprising my invention along a horizontal plane with the concave members or bodies for receiving the reflecting coating in place therein; Fig. 2 is a side elevation of said apparatus; and Fig. 3 is a corresponding sectional view of a The manner of operation first requires the.

bodies M of the coating material to be inserted in the heater l3. This operation consists, in this particular instance, in inserting relatively long narrow strips'of aluminum in the two separate coil portions ll of the heater i3 on opposite sides of the head I 0. The said coil portions H are part of the single tungsten wire making up said heater l3. Each of the strips I4 provides sufficient coating material for a single cup l2. In each instance, the heater coil I! must bear a d'eflnite relation to the associated cup l2, and it is located on a central axis through the head 10 and extends outwardly from one face thereof from substantially the outermost surface of the gasket i8l8 to be drawn down to grip said ends of the heater l3. The rods |8-l8 are also used to carry the electrical energy to the heaters and are therefore mounted in th'einsulating bushing 20 and 2| in the head I0 and threaded sleeve 22 respectively. Rubber washers 23 on opposite sides of the flange 24 on each rod I8 are compressed by pressure of the sleeve 22 so that they seal said rod 1 l8 air-tight in the head i0.

modification of my apparatus for coating diifer- The said head I is metal terminal elements and basing purposes,

and those shown in Fig. 3 being somewhat more shallow and almost double the diameter of the former. Both cups i 2 are completely sealed except for a passage 28 extending through a tube 29 attached thereto which permits the lamp to be exhausted and gas fllled at some other stage in its manufacture and another duty of the operator is to close off said passage 28, A convenient method of sealing the passage 28 is 'to force therubber tube 30, already stopped by the plug 3!, over the end of the exhaust tube 29. Some means such as the movable holder 32 is preferably provided to keep the cups I! in position in the apparatus,

The interior of the head I3 and the cups l2 can now be evacuated as they-together form a sealed enclosure or chamber. The evacuation takes place through means (not shown) connected to the passage IS in the ring-shaped body i and is preferably carried on until the interior pressure. is between 25 and micronsof mer-. cury. In the course of the evacuation cycle, it may be desirable to flush and exhaust the interior of the cups l2 repeatedly to assist in clearing contamination therefrom.

To facilitate the thorough removal of the contamination from all parts of each cup l2' and particularly about the rim portion thereof, the opening or chamber formed by the interior of the head I0 is partially closed off by the annular as possible to the interior of the particular cup M in which it is vaporized so that it does not deposit on the opposite cup l2 and is distributed more uniformly and satisfactorily over the adjacent surface of the near cup-l2. I have found that when such partitions 33 are not provided. the coating material traveling from one cup J! to the other passes through the space containing the greatest contamination and is apt to leave an uneven-and discolored deposit on the latter cup. Because of the particular shape of the rim 23 of the cup I! and the location of the outer face of the partition 33 which is aligned with the endmost portion of the heat coil II, the coating material does not tend to deposit on said rim 25 or the gasket ll. Following the interval of operation of the heaters in which the coating material (aluminum, in this instance) is vaporized and deposits on the cups i2, air is admitted into the apparatus and the holders 3! are pulled back, releasing the cups l2.

' I What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for coating surfaces by thermal evaporation comprising a ring-shaped head partition or baiiie 33 which fits loosely in the member having a-sealing gasket at each side thereof, means for supporting a pair of cupshaped bodies in opposed relationship with their mouths pressed against the said gaskets, said head member having an exhaust opening through the wall thereofv between its sides for evacuation of the chamber formed by'said head-- and cup-shaped bodies, a pair ofselectrical heating elements each having associated'itherewith a quantity of coating metal, said heating elements being supported by said head and located respectively in the space enclosed by each of said cup-shaped bodies so as to vaporize the coating metal and deposit it on the inner surface of the cup-shaped body surrounded thereby, and shield means arranged within said head in position to intercept at least a substantial part of the metal vaporizedfrom one of said heating elements and directed toward the cup-shaped body surrounding the other heating element.

2. Apparatus for coating surfaces by thermal evaporation comprising a ring-shaped head member having a sealing gasket at each side thereof, means for supporting a pair of cupshaped bodies in opposed relationship with-their mouths pressed against the said gaskets, said head member having an exhaust opening through the wall thereof between its sides for evacuation of the chamber formed by said head and cupshaped bodies, a pair of electrical heating elements each having associated therewith a quantity of coating metal, said heating elements bein supported by said head and located respectively in the space enclosed by each of said cup-shaped bodies so as to vaporize the coating metal and deposit it on the inner surface of the cup-shaped body surrounded thereby, and shield means comprising a pair of annular baiiie rings located at the interior of said ring-shaped head on opposite sides of the exhaust opening therein to intercept metal vaporized from one of said heating elements and directed toward the cup-shaped body surrounding the other heating element.

- CARL LENZ. 

